Late-time cosmological approach in mimetic f(R, T) gravity

Baffou, Etienne; Houndjo, M. J. S.; Hamani-Daouda, M.; Alvarenga, F. G.

doi:10.1140/epjc/s10052-017-5291-x

Cited by 47 publications

(24 citation statements)

References 64 publications

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“…Another modified scenario that has been proposed recently is the mimetic gravity one [35]. Mimetic theory has many applications in cosmology [36,37,[39][40][41] as well as in the solar system [42][43][44][45][46], see also the recent review [47].…”

Section: Introductionmentioning

confidence: 99%

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Charged rotating black holes coupled with nonlinear electrodynamics Maxwell field in the mimetic gravity

Nashed

Hanafy

Bamba

2019

J. Cosmol. Astropart. Phys.

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In mimetic gravity, we derive D-dimension charged black hole solutions having flat or cylindrical horizons with zero curvature boundary. The asymptotic behaviours of these black holes behave as (A)dS. We study both linear and nonlinear forms of the Maxwell field equations in two separate contexts. For the nonlinear case, we derive a new solution having a metric with monopole, dipole and quadrupole terms. The most interesting feature of this black hole is that its dipole and quadruple terms are related by a constant. However, the solution reduces to the linear case of the Maxwell field equations when this constant acquires a null value. Also, we apply a coordinate transformation and derive rotating black hole solutions (for both linear and nonlinear cases). We show that the nonlinear black hole has stronger curvature singularities than the corresponding known black hole solutions in general relativity. We show that the obtained solutions could have at most two horizons. We determine the critical mass of the degenerate horizon at which the two horizons coincide. We study the thermodynamical stability of the solutions. We note that the nonlinear electrodynamics contributes to process a second-order phase transition whereas the heat capacity has an infinite discontinuity.

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Section: Introductionmentioning

confidence: 99%

“…Hence, the pure AdS solution is only stable at temperatures T < T max . Above T max , only the heavy black holes would have stable configurations[103].Next we evaluate the horizon heat capacity C h , therefore we substitute Eqs (41). and(44)into Eq (40)…”

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confidence: 99%

Charged rotating black holes coupled with nonlinear electrodynamics Maxwell field in the mimetic gravity

Nashed

Hanafy

Bamba

2019

J. Cosmol. Astropart. Phys.

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“…The mimetic framework was further studied in Refs. [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] and also for a recent concise review on mimetic gravity see [60]. To our opinion, the most appealing features of mimetic gravity [41], and also of mimetic F (R) gravity [49], is firstly the fact that dark matter may be described in a geometric way without the need of the particle description [61], and secondly, in many cases a viable inflationary era may be predicted, which can be in concordance with the latest Planck [2] and also with the BICEP2/Keck-Array data [62].…”

Section: Introductionmentioning

confidence: 99%

The reconstruction of f(ϕ)R and mimetic gravity from viable slow-roll inflation

Odintsov

Oikonomou

2018

Nuclear Physics B

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In this work, we extend the bottom-up reconstruction framework of F (R) gravity to other modified gravities, and in particular for f (φ)R and mimetic F (R) gravities. We investigate which are the important conditions in order for the method to work, and we study several viable cosmological evolutions, focusing on the inflationary era. Particularly, for the f (φ)R theory case, we specify the functional form of the Hubble rate and of the scalar-to-tensor ratio as a function of the efoldings number and accordingly, the rest of the physical quantities and also the slow-roll and the corresponding observational indices can be calculated. The same method is applied in the mimetic F (R) gravity case, and in both cases we thoroughly analyze the resulting free parameter space, in order to show that the viability of the models presented is guaranteed and secondly that there is a wide range of values of the free parameters for which the viability of the models occurs. In addition, the reconstruction method is also studied in the context of mimetic F (R) = R gravity. As we demonstrate, the resulting theory is viable, and also in this case, only the scalar-to-tensor ratio needs to be specified, since the rest follow from this condition. Finally, we discuss in brief how the reconstruction method could function for other modified gravities.PACS numbers: 04.50. Kd, 95.36.+x, 98.80.Cq,

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“…Alvarenga et al [9] investigated the cosmology of scalar perturbations for a flat FRW spacetime, in the realm of a specific form of f (R, T) DE model. Baffou et al [10] explored the late-time cosmic evolution in f (R, T) model of gravity, under the effect of Lagrange multipliers and mimetic potentials. Yousaf at el.…”

Section: Introductionmentioning

confidence: 99%

$f(\mathcal{G},T_{αβ}T^{αβ})$ Theory and Complex Cosmological Structure

Yousaf,

Bhatti,

Khan

et al. 2021

Preprint

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The basic objective of this investigation is to explore the impact of a novel gravitational modification, specifically, the f (G, T 2 ) (where G := R 2 + R αβσς R αβσς − 4R αβ R αβ and T 2 := T αβ T αβ , T αβ denotes the stress-energy tensor) model of gravitation, upon the complexity of time-dependent dissipative as well as non-dissipative spherically symmetric celestial structures. To find the complexity factor (CF) from the generic version of the structural variables, we performed Herrera's scheme for the orthogonal cracking of Riemann tensor. In this endeavor, we are mainly concerned with the issue of relativistic gravitational collapse of the dynamically relativistic spheres fulfilling the presumption of minimal CF. The incorporation of a less restrictive condition termed as quasi-homologous (QH) condition together with the zero CF, allows us to formulate a range of exact solutions for a particular choice of f (G, T 2 ) model. We find that some of the given exact solutions relax the Darmois junction conditions and describe thin shells by satisfying the Israel conditions, while some exhibit voids by fulfilling the Darmois constraints on both boundary surfaces. Eventually, few expected applications of the provided solutions in the era of modern cosmology are debated.

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Late-time cosmological approach in mimetic f(R, T) gravity

Cited by 47 publications

References 64 publications

Charged rotating black holes coupled with nonlinear electrodynamics Maxwell field in the mimetic gravity

Charged rotating black holes coupled with nonlinear electrodynamics Maxwell field in the mimetic gravity

The reconstruction of f(ϕ)R and mimetic gravity from viable slow-roll inflation

$f(\mathcal{G},T_{αβ}T^{αβ})$ Theory and Complex Cosmological Structure

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